Maternal Weight Associated with Adverse Pregnancy Outcomes

Updated on October 17, 2018

Women who are overweight and obese during pregnancy are more apt to need advanced medical care, according to a research study published in BJOG: An International Journal of Obstetrics and Gynaecology. The study, completed in conjunction with researchers at Queen’s University in Belfast, found severe adverse side effects for both the infant and mother in mothers who were overweight or obese at the time of pregnancy and delivery.

Obesity is taking the world by storm. The World Health Organization sets body mass index (BMI) ratings by which overall health can be loosely determined. The classifications include underweight, normal weight, overweight and three classes of obesity.

Researchers investigated more than 30,000 singleton births in Ireland. All pregnancies took place between 2004 and 2011. Among the pregnant women, less than 3% were considered underweight, about 53% fell into the normal weight category, and 28% were classified as overweight. The obesity group was made up of 17% of women with the majority falling into the obesity I subclass, with BMI measurements between 30 and 34.9.

When adverse pregnancy, maternal and neonatal outcomes in normal weight pregnancies were compared to outcomes of overweight and obese pregnancies, there was a clear difference. Women in the overweight and obese I categories were at equally increased risk of gestational diabetes, hypertension, C-section and postpartum blood loss. Women in obesity 2 and obesity 3 subcategories were at higher risk than overweight and obesity 1 categories that paralleled the increase in overall BMI.

Researchers also noted neonatal risk, especially in the obesity 3 subgroups. Infants born to women in this subgroup were three times more likely to be admitted to the NICU (neonatal intensive care unit) than other infants. Infants were also more likely to be delivered prematurely, associated with long-term risk of health problems.

Being overweight or obese has always come with increased risk of maternal and/or neonatal side effects. Researchers were able to narrow down the effect of obesity more precisely by placing study participants in three obesity subclasses.